Stair structure.



No. 811,436. PATENTBD JAN. 80, 1906.

M. PLOTKIN.

STAIR STRUCTURE.

APPLIUATION FILED MAR.16, 1905.

rinirnn srarps enrnnr OFFICE.

MAX PLOTKIN, OF NEW YORK, N. Y, ASSIGNOR TO CLARA BOIS, OF BROOKLYN, NEWYORK.

STABR STWUCTURE Patented Jan. 30, 1906.

Application filed March 1,6, 1905. Serial No. 250,431.

To all whom it may concern:

Be it known that 1, MAX PLOTK1N,a citizen of the United States, and aresident of the city of New York, borough of Brooklyn, in the county ofKings and State of New York, have. invented a new and Improved StairStructure, of which the following is a full, clear, and exactdescription.

This invention relates to im )rovements in the construction ofsheet-meta stairs, the object being to provide a metal stairs with ameans for securing rock-asphalt, concrete, or the like on the treads insuch a manner as to prevent breaking or cracking thereof.

' Other objects of the invention will appear in the eneral description.

I wi 1 describe a stair structure embodying my invention and then pointout the novel features in the ap ended claims.

Reference is to e had to the accoin )anying drawin s, forming a part ofthis speci cation, in whic similar characters of reference indicatecorresponding parts in all the figures.

Figure 1 is a side elevation, partly in section, of a stair structureembodying my invention. Fig. 2 is a section on the line :1; m of Fig. 1.Fig. 3 is a'scction on the line y y of Fig. 1, and Fig. 4 is a sectionaldetail showing a modification.

Referring to the drawings, 1 designates the tread of the stair, and 2the riser, which as here shown are formed in one single sheet of metal.At the wall side the treads and risers are bolted to angle-plates 3,which are secured to ledges 4 on a string-piece 5, bolted orotherwisesecured to the wall, and. at the o posite end the stairs aresecured to angle- E ates 6 in the form oi string-picccs. At the ase orlower portion of the riser 2 1s a channel or reentrant portion 7, inWhich rock-asphalt or concrete 8 may be keyed, and the' stringpieceshave triangular lip portions 8 turned against the lower portions of therisers. These reentrant portions are indicated as V-shaped; but they maybe otherwise shaped without departing from the spirit of my invention.At the front of each step is a nosing, which in. Fig. l is formedintegral with the riser, the said nosing being curved outholds theconcrete from slipping.

any metallic stair structure.

Ward and upward, as indicated at 9, and at the upper edge is adownwardly and outwardly inclined flange 10. This nosing forms a pocketto receive the outer edge of the concrete 'or the like, and the flange10 firmly The steps may be secured to the stringpiece 5 by means ofeyebolts 11, which pass through openings in said string-piece, and

bolts 12 pass through the treads or steps and also through the eyes ofthe bolts.

. In Fig. 4.1 have shown a nosing 13 formed independent of the tread orriser and of thicker metal than the nosin first described. This nosing13 may be readily attached to Having thus described my invention, Iclaim as new and desireto secure by Letters Patent- 1. In a stairstructure, a nosing forlnin a pocket and having a-downwardly-exten edflange at its upper edge.

2. In a stair structure, a nosing forinin a pocket and having adownwardly exten ed and inclined flange at its upper edge.

3. In a stair structure, a tread and a riser having a reentrant at itslower portion above the tread.

4:. In a stair structure,'a tread and riser consisting of a single sheetof metaLthe riser having a reentrant at its lowerportion, and a nosingformed on its upper portion.

5. In a stair structure, a tread and riser, consistingof a singlesheetof metal, the riser having-a rentrant at its lower portion, a nosingforming a pocket, and a downwardly-inclined flange at the upper edge ofsaid nosing.

6. In a metal stair structure, a string-piece bent to form a ledgeat itslower portion,

treads and risers, angle-plates secured to the treads and users and tosaid ledge, and means

